Modified carbon products and ink jet inks, inks and coatings containing modified carbon products

ABSTRACT

A modified carbon product is described which comprises carbon having attached at least one organic group. The organic group comprises a) at least one aromatic group or a C 1  -C 12  alkyl group and b) at least one ionic group, at least one ionizable group, or a mixture of an ionic group and an ionizable group. The aromatic group or the C 1  -C 12  alkyl group of the organic group is directly attached to the carbon and the organic group is present at a level of from about 0.10 to about 4.0 micromoles/m 2  of the carbon used based on nitrogen surface area of the carbon. Also described are aqueous and non-aqueous inks and coatings and ink jet ink compositions containing the modified carbon product. A method to increase the flow of an ink, as measured by glass plate flow, by incorporating the modified carbon product as part of the ink is also disclosed as well as a method to improve the waterfastness of a print imaged by an ink composition. Lastly, non-aqueous ink and coating formulations are described which contain an appropriate solvent and a modified carbon product comprising carbon having attached at least one organic group, wherein the organic group comprises a) at least one aromatic group or C 1  -C 12  alkyl group, and b) at least one ionic group, at least one ionizable group, or a mixture of an ionic group and an ionizable group, wherein the organic group is present in any amount.

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/663,707, filed Jun. 14, 1996, now U.S. Pat. No. 5,707,432which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to modified carbon products and inks and coatingswhich contain modified carbon products. The present invention is furtherdirected to ink compositions and, more particularly, to aqueous inkcompositions suitable for imaging applications, such as ink jet printingprocesses.

2. Discussion of the Related Art

Presently, predominant black pigments are carbon blacks such as furnaceblacks which can be used as colorants either in dry, powdered form, aflushed paste, or liquid concentrate form. Generally, the form of thecolorant influences the hue, permanency, bulk, opacity, gloss, rheology,end use, and print quality.

There are various classifications of inks used presently. Thesecategories include printing inks, ultraviolet cure inks, ball-pointinks, and stamp pad or marking inks. Generally, inks can be applied byletter press, lithographic, flexographic, gravure, silk screen, stencil,duplicating, and electrostatic. Inks thus can be found in such end usesas news, publication, commercial, folding carton, book, corrugated box,paper bag, wrapper, label, metal container, plastic container, plasticfilm, foil, laminating, food insert, sanitary paper, textile and thelike. McGraw-Hill's Encyclopedia of Science and Technology, Vol. 7, pgs.159-164, provides further details of the types of inks available andtheir uses, all of which is incorporated herein by reference.

Coatings can contain pigments as well and are used for decorative,protective, and functional treatments of many kinds of surfaces. Thesesurfaces include, coils, metals, appliances, furniture, hardboard,lumber and plywood, marine, maintenance, automobile, cans, andpaperboard. Some coatings, such as those on undersea pipelines, are forprotective purposes. Others, such as exterior automobile coatings,fulfill both decorative and protective functions. Still others providefriction control on boat decks or car seats. Some coatings control thefouling of ship bottoms, others protect food and beverages in cans.Silicon chips, printed circuit panels, coatings on waveguide fibers forsignal transmission, and magnetic coatings on video tapes and computerdisks are among many so-called hi-tech applications for coatings.

Categories of aqueous vehicles for aqueous inks and coatings includethose in which the binder is soluble in water, those in which it iscolloidally dispersed, and those in which it is emulsified to form alatex. The combination of binder and volatile liquid is called thevehicle which may be a solution or a dispersion of fine binder particlesin a non-solvent. Pigments are finely divided, insoluble, solidparticles dispersed in the coating vehicle and distributed throughoutthe binder in the final film. Surfactants can be used as pigmentdispersants. The components and manufacturing of aqueous coatings arefurther discussed in the Concise Encyclopedia of Polymers, Science andEngineering, pgs. 160-171 (1990), which is incorporated herein byreference.

Non-aqueous inks and coatings are used for many applications in whichaqueous vehicles are not suitable. For instance, inks which are to beprinted on hydrophobic, non-porous substrates such as metal, glass, orplastics must be fast-drying. Therefore, solvents such as ketones,esters, alcohols, or hydrocarbons are often used instead of water. Suchsolvent-based inks are used widely for industrial labeling of cardboardboxes and various metal or plastic containers and components. Specificexamples include news ink compositions and web off-set gloss heat-setink compositions.

Inks and coatings are also required to be water resistant in certainsituations. In such instances, water-resistant resins can be dissolvedin non-aqueous solvents of ink and coating formulations to provide thedesired water resistance upon drying. A primary use of such non-aqueouscoatings is on metal and plastic automotive parts.

Ink jet printing is a non-impact process wherein droplets of ink areproduced and deposited on a substrate such as paper, transparent film,or textile material in response to an electronic signal. Ink jetprinting systems are typically classified by two known types: continuousstream or drop-on-demand.

Ink compositions which are useful in imaging applications, such as inkjet ink printing systems, are well known and generally contain watersoluble dyes. Although dye-based inks are suitable for their intendedpurposes, dyes have several disadvantages when used in ink jet inks. Forexamples, dyes, being water-soluble in a water/organic mixture, maydissolve and run when exposed to moisture or water. Dye images mayfurther smear or rub off on contact with felt pen markers or upon beingrubbed or touched by finger. Dyes also exhibit poor light stability whenexposed to visible or ultraviolet light.

Pigments are also known as colorants in ink compositions but have notreceived a wide degree of acceptance in ink jet ink systems, forexample, because of problems associated with the performance andreliability of the composition, i.e., print properties, stability,latency, and the like.

As a result, although known compositions are suitable for their intendedpurpose, a need remains for improved ink compositions, especially foruse in the ink jet printers, which overcome the problems typicallyassociated with current dye-based and pigment system. In addition, thereis a need for improved ink compositions providing good print propertiesand generating printed images having improved waterfastness.

SUMMARY OF THE INVENTION

The present invention relates to a modified carbon product comprisingcarbon having attached at least one organic group. The organic groupcomprises a) at least one aromatic group or a C₁ -C₁₂ alkyl group and b)at least one ionic group, at least one ionizable group, or a mixture ofan ionic group and an ionizable group. The aromatic group or the C₁ -C₁₂alkyl group is directly attached to the carbon and the organic group ispresent at a level of from about 0.10 to about 4.0 micromoles/m².

The present invention also relates to a coating or ink composition,aqueous or non-aqueous, comprising the above-described modified carbonproduct. The present invention in addition relates to ink jet inkcompositions comprising the above-described modified carbon product.

The present invention further relates to a non-aqueous coating or inkcomposition comprising a modified carbon product and a non-aqueoussolvent. The modified carbon product comprises carbon having attached atleast one organic group wherein the organic group comprises a) at leastone aromatic group or a C₁ -C₁₂ alkyl group and b) at least one ionicgroup, at least one ionizable group, or a mixture of an ionic group andan ionizable group. The aromatic group or the C₁ -C₁₂ alkyl group isdirectly attached to the carbon and there is no limit on the amount oforganic group that can be present.

Carbon, as used herein, may be of the crystalline or amorphous type.Examples include, but are not limited to, graphite, carbon black, carbonfiber, vitreous carbon, and activated charcoal or activated carbon.Finely divided forms of the above are preferred; also, it is possible toutilize mixtures of different carbons.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The modified carbon product of the present invention comprises carbonhaving attached thereto at least one organic group. This organic groupcomprises a) at least one aromatic group or a C₁ -C₁₂ alkyl group and b)at least one ionic group, at least one ionizable group, or a mixture ofan ionic group and an ionizable group. The aromatic group or the C₁ -C₁₂alkyl group of the organic group is directly attached to the carbon.Further, the organic group is present at a level of from about 0.10 toabout 4.0 micromoles/m².

The carbon may be of the crystalline or amorphous type. Examplesinclude, but are not limited to, graphite, carbon black, vitreouscarbon, activated charcoal, carbon fiber, activated carbon, and mixturesthereof. Finely divided forms of the above are preferred; also, it ispossible to utilize mixtures of different carbons.

The modified carbon products may be prepared preferably by reactingcarbon with a diazonium salt in a liquid reaction medium to attach atleast one organic group to the surface of the carbon. The diazonium saltmay contain the organic group to be attached to the carbon. A diazoniumsalt is an organic compound having one or more diazonium groups.Preferred reaction media include water, any medium containing water, andany medium containing alcohol. Water is the most preferred medium.Examples of modified carbon products, wherein the carbon is carbonblack, and various preferred methods for their preparation are describedin U.S. patent application Ser. No. 08/356,660 entitled "Reaction ofCarbon Black with Diazonium Salts, Resultant Carbon Black Products andTheir Uses," filed Dec. 15, 1994 now abandoned and itscontinuation-in-part application, U.S. patent application Ser. No.08/572,525, filed Dec. 14, 1995, now U.S. Pat. No. 5,673,461 both ofwhich are incorporated herein by reference. Examples of modified carbonproducts, wherein the carbon is not carbon black, and various preferredmethods for their preparation are described in patent application Ser.No. 08/356,653 entitled "Reaction of Carbon Materials With DiazoniumSalts and Resultant Carbon Products," filed Dec. 15, 1994, now U.S. Pat.No. 5,554,739, also incorporated herein by reference.

In the preferred preparation of the above modified carbon products, thediazonium salt need only be sufficiently stable to allow reaction withthe carbon. Thus, that reaction can be carried out with some diazoniumsalts otherwise considered to be unstable and subject to decomposition.Some decomposition processes may compete with the reaction between thecarbon and the diazonium salt and may reduce the total number of organicgroups attached to the carbon. Further, the reaction may be carried outat elevated temperatures where many diazonium salts may be susceptibleto decomposition. Elevated temperatures may also advantageously increasethe solubility of the diazonium salt in the reaction medium and improveits handling during the process. However, elevated temperatures mayresult in some loss of the diazonium salt due to other decompositionprocesses. The diazonium salts may be prepared in situ. It is preferredthat the modified carbon products of the present invention contain noby-products or unattached salts.

In the preferred process of preparation, carbon black can be reactedwith a diazonium salt when present as a dilute, easily stirred, aqueousslurry, or in the presence of the proper amount of water for carbonblack pellet formation. If desired, carbon black pellets may be formedutilizing a conventional pelletizing technology. Other carbons can besimilarly reacted with the diazonium salt. In addition, when modifiedcarbon products utilizing carbon other than carbon black are, forinstance, used in non-aqueous inks and coatings, the carbon shouldpreferably be ground to a fine particle size before reaction with thediazonium salt in the preferred process to prevent unwantedprecipitation of the modified carbon product in the inks and coatings.In addition, when modified carbon products utilizing carbon other thancarbon black are used in ink jet inks, the carbon should preferably beground to a fine particle size before reaction with the diazonium saltin the preferred process to prevent unwanted precipitation in the ink.An additional means of stabilization of the particles may be necessaryin ink jet inks when the amounts of organic groups on the carbon are notsufficient to provide colloidal stability. One such means can be the useof a polymeric dispersant.

For purposes of one embodiment of the present invention, the amount oforganic group attached to the carbon is important for purposes of thesubsequent use of the modified carbon product in such applications asink jet ink compositions, coating formulations, and ink systems. Inparticular, the levels should be of a low level. In other words, thelevels of organic group may be from about 0.10 to about 4.0micromoles/m² of the carbon used, preferably from about 1.5 to about 3.0micromoles/m² based on nitrogen surface area of the carbon.

It was quite unexpected and surprising that carbon having low levels ofattached organic groups would result in better properties than carbonhaving higher levels of attached carbon groups and/or untreated carbonproducts. It was commonly believed that the higher the amount of organicgroup attached to the carbon, the better the properties. However, incertain situations, attaching low levels of organic groups to carbonresults in better properties. These better properties have been seen,for instance, with the use of the modified carbon products of thepresent invention in non-aqueous applications such as non-aqueous inksystems including non-aqueous gloss ink system and non-aqueous coatingformulations. When the modified carbon products of the present inventionhave been used in these systems and formulations, improved jetness, blueundertone, and gloss have been achieved and in certain situations, therheology of the ink, as measured by the Laray viscosity, spreadometervalues, and vertical glass plate flow properties have been modified. Insome ink formulations, flow was increased considerably over that ofuntreated carbon products. In addition, in some ink formulations, suchas ink jet ink, improved waterfastness of the printed image wasachieved.

As stated earlier, the organic group comprises an aromatic group or a C₁-C₁₂ alkyl group. The aromatic group includes, but is not limited to,unsaturated cyclic hydrocarbons containing one or more rings. Thearomatic group may be substituted or unsubstituted. Aromatic groupsinclude aryl groups (for example, phenyl, naphthyl, anthracenyl, and thelike), and heteroaryl groups (imidazolyl, pyrazolyl, pyridinyl, thienyl,thiazolyl, furyl, triazinyl, indolyl, and the like). The C₁ -C₁₂ alkylgroup may be branched or unbranched and is preferably ethyl.

An ionizable group is one which is capable of forming an ionic group inthe medium of use. The ionic group may be an anionic group or a cationicgroup and the ionizable group may form an anion or a cation.

Ionizable functional groups forming anions include, for example, acidicgroups or salts of acidic groups. The organic groups, therefore, caninclude groups derived from organic acids. Preferably, when the organicgroup contains an ionizable group forming an anion, the organic grouphas a) an aromatic group or a C₁ -C₁₂ alkyl group and b) at least oneacidic group having a pKa of less than 11, or at least one salt of anacidic group having a pKa of less than 11, or a mixture of at least oneacidic group having a pKa of less than 11 and at least one salt of anacidic group having a pKa of less than 11. The pKa of the acidic grouprefers to the pKa of the organic group as a whole, not just the acidicsubstituent. More preferably, the pKa is less than 10 and mostpreferably less than 9. The aromatic group may be further substituted orunsubstituted, for example, with alkyl groups. More preferably, theorganic group is a phenyl or a naphthyl group and the acidic group is asulfonic acid group, a sulfinic acid group, a phosphonic acid group, ora carboxylic acid group. Examples include --COOH, --SO₃ H and --PO₃ H₂,--SO₂ NHCOR, and their salts, for example --COONa, --COOK, --COO⁻ NR₄ ⁺,--SO₃ Na, --HPO₃ Na, --SO₃ ⁻ NR₄ ⁺, and PO₃ Na₂, where R is a saturatedor unsaturated alkyl or phenyl group. Particularly preferred ionizablesubstituents are --COOH and --SO₃ H and their sodium and potassiumsalts.

Accordingly, it is preferred that the carbon is treated with aryldiazonium salts containing at least one acidic functional group.Examples of aryl diazonium salts include, but are not limited to, thoseprepared from sulfanilic acid, 4-aminobenzoic acid, 4-amino salicylicacid, 7-amino-4-hydroxy-2-naphthlenesulfonic acid, aminophenylboronicacid, aminophenylphosphonic acid, and metanilic acid.

The organic group can be a substituted or unsubstituted sulfophenylgroup or a salt thereof; a substituted or unsubstituted(polysulfo)phenyl group or a salt thereof; a substituted orunsubstituted sulfonaphthyl group or a salt thereof; or a substituted orunsubstituted (polysulfo)naphthyl group or a salt thereof One example ofa sulfophenyl group is hydroxysulfophenyl group or a salt thereof.

Specific organic groups having an ionizable functional group forming ananion are p-sulfophenyl and 4-hydroxy-3-sulfophenyl.

Amines represent examples of ionizable functional groups that formcationic groups and can be attached to the same organic groups asdiscussed above for the ionizable groups which form anions. For example,amines may be protonated to form ammonium groups in acidic media.Preferably, an organic group having an amine substituent has a pKb ofless than 5. Quaternary ammonium groups (--NR₃ ⁺) and quaternaryphosphonium groups (--PR₃ ⁺) also represent examples of cationic groupsand can be attached to the same organic groups as discussed above forthe ionizable groups which form anions. Preferably, the organic groupcontains an aromatic group such as a phenyl or a naphthyl group and aquaternary ammonium or a quaternary phosphonium group. Quaternizedcyclic amines, and quaternized aromatic amines, can also be used as theorganic group. Thus, N-substituted pyridinium compounds, such asN-methyl-pyridyl, can be used in this regard. Examples of organic groupsinclude, but are not limited to, 3-C₅ H₄ N(C₂ H₅)⁺ X⁻, C₆ H₄ NC₅ H₅ ⁺X⁻, C₆ H₄ COCH₂ N(CH₃)₃ ⁺ X⁻, C₆ H₄ COCH₂ (NC₅ H₅)⁺ X⁻, 3-C₅ H₄ N(CH₃)⁺X⁻, C₆ H₄ N(CH₃)₃ ⁺ X⁻, and C₆ H₄ CH₂ N(CH₃)₃ ⁺ X⁻, wherein X⁻ is ahalide or an anion derived from a mineral or organic acid. Otherexamples include pC₆ H₄ --SO₃ ⁻ Na⁺, pC₆ H₄ --CO₂ Na⁺, and C₅ H₄ N⁺(NO₃)^(-C) ₆ H₅.

Additional optional functional groups which may be present on theorganic group include, but are not limited to, R, OR, COR, COOR, OCOR,halogen, CN, NR₂, SO₂ NR(COR), SO₂ NR₂, NR(COR), CONR₂, NO₂, SO₃ M, SO₃NR₄, and N═NR'. R is independently hydrogen, C₁ -C₂₀ substituted orunsubstituted alkyl (branched or unbranched), C₃ -C₂₀ substituted orunsubstituted alkenyl, (C₂ -C₄ alkyleneoxy)_(x) R", or a substituted orunsubstituted aryl. R' is independently hydrogen, C₁ -C₂₀ substituted orunsubstituted alkyl (branched or unbranched), or a substituted orunsubstituted aryl. R" is hydrogen, a C₁ -C₂₀ substituted orunsubstituted alkyl, a C₃ -C₂₀ substituted or unsubstituted alkenyl, aC₁ -C₂₀ substituted or unsubstituted alkanoyl, or a substituted orunsubstituted aroyl. M is H, Li, Na, Cs, or K. The integer x ranges from1-40 and preferably from 2-25.

Another example of an organic group is an aromatic group of the formulaA_(y) Ar--, which corresponds to a primary amine of the formula A_(y)ArNH₂. In this formula, the variables have the following meanings: Ar isan aromatic radical selected from the group consisting of phenyl,naphthyl, anthracenyl, phenanthrenyl, biphenyl, pyridinyl, andtriazinyl; A is a substituent on the aromatic radical independentlyselected from a functional group described above or A is a linear,branched or cyclic hydrocarbon radical (preferably containing 1 to 20carbons), unsubstituted or substituted with one or more of thosefunctional groups; and y is an integer from 1 to 5 when Ar is phenyl, 1to 7 when Ar is naphthyl, 1 to 9 when Ar is anthracenyl, phenanthrenyl,or biphenyl, or 1 to 4 when Ar is pyridinyl, or 1 to 2 when Ar istriazinyl. When A is a (C₂ -C₄ alkyleneoxy)_(x) R" group, it ispreferably a polyethoxylate group, a polypropoxylate group, or a randomor block mixture of the two.

Another example of a modified carbon product comprises carbon and anattached organic group having a) an aromatic group or a C₁ -C₁₂ alkylgroup and b) at least one group of the formula SO₂ NR₂ or SO₂ NR(COR). Ris independently hydrogen, a C₁ -C₂₀ substituted or unsubstituted alkyl,a C₃ -C₂₀ substituted or unsubstituted alkenyl, (C₂ -C₄ alkyleneoxy)_(x)R' or a substituted or unsubstituted aryl; R' is hydrogen, a C₁ -C₂₀substituted or unsubstituted alkyl, a C₃ -C₂₀ substituted orunsubstituted alkenyl, a C₁ -C₂₀ substituted or unsubstituted alkanoylor substituted or unsubstituted aroyl; and x is from 1 to 40. Aromaticgroups include p-CH₄ SO₂ NH₂, p-C₆ H₄ SO₂ NHC₆ H₁₃, p-C₆ H₄ SO₂ NHCOCH₃,p-C₆ H₄ SO₂ NHCOC₅ H₁₁ and p-C₆ H₄ SO₂ NHCOC₆ H₅.

As stated earlier, the modified carbon products above are useful innon-aqueous ink formulations. Thus, the invention provides an improvedink composition containing a suitable solvent and a modified carbonproduct having attached an organic group comprising a) a substituted orunsubstituted aromatic group or a C₁ -C₁₂ alkyl group and b) at leastone ionic group, at least one ionizable group or a mixture of an ionicgroup and an ionizable group. Other known ink additives may beincorporated into the ink formulation. It is also within the bounds ofthe present invention to use an ink formulation containing a mixture ofunmodified carbon with the modified carbon products.

In general, an ink includes a colorant or pigment and solvents to adjustviscosity and drying. An ink may optionally further include a vehicle orvarnish which functions as a carrier during printing and/or additives toimprove printability, drying, and the like. For a general discussion onthe properties, preparation and uses of inks, see The Printing Manual,5th Ed., R. H. Leach, et al, Eds. (Chapman & Hall, 1993).

The modified carbon products of the invention can be incorporated intoan ink formulation using standard techniques either as a predispersionor as a solid. Use of the modified carbon products of the presentinvention may provide a significant advantage and cost savings byreducing the viscosity of the formulation. This may also allow higherloading of carbon product in a formulation. The milling time may bereduced as well. The modified carbon products of the present inventionmay also provide improved jetness, blue tone, and gloss.

The modified carbon products above may also be used in non-aqueouscoating compositions such as paints or finishes. Thus, an embodiment ofthe present invention is a coating composition containing a suitablesolvent and the modified carbon product of the present invention. Otherconventional coating additives may be incorporated into the non-aqueouscoating compositions such as a binder.

Non-aqueous coating formulations vary widely depending on the conditionsand requirements of final use. In general, coating systems contain up to30% by weight carbon. The resin content can vary widely up to nearly100%. Examples include acrylic, alkyd, urethane, epoxy, cellulosics, andthe like. Solvent content may vary between 0 and 80%. Examples includearomatic hydrocarbons, aliphatic hydrocarbons, alcohols, polyalcohols,ketones, esters, and the like. Two other general classes of additivesare fillers and modifiers. Examples of fillers are other coloringpigments, clays, talcs, silicas, and carbonates. Fillers can be added upto 60% depending on final use requirements. Examples of modifiers areflow and leveling aids and biocides generally added at less than 5%. Themodified carbon products of the present invention can be incorporatedinto a non-aqueous coating composition using standard techniques eitheras a predispersion or as a solid.

Examples of non-aqueous media for the incorporation of compositionscontaining the modified carbon products of the present inventioninclude, but are not limited to, melamine-acrylic resins, melamine-alkydresins, urethane-hardened alkyd resins, urethane-hardened acrylicresins, and the like. The modified carbon products of the presentinvention may also be used in aqueous emulsion paints. In these types ofpaints, there is a non-aqueous portion containing the pigment whereinthe non-aqueous portion is then dispersed in the aqueous paint.Accordingly, the modified carbon products of the present invention canbe used as part of the non-aqueous portions which is then dispersed intothe aqueous emulsion paints.

The modified carbon products of the present invention are also useful inaqueous ink and coating formulations. Aqueous includes mixtures of waterand other water-miscible or -dispersible substances, such as an alcohol.Thus, the invention provides an aqueous ink composition comprising waterand a modified carbon product according to the invention. Other knownaqueous ink additives may be incorporated into the aqueous inkformulation. As stated previously, an ink may consist of the variouscomponents described above. Various aqueous ink compositions are alsodisclosed, for example, in U.S. Pat. Nos. 2,833,736; 3,607,813;4,104,833; 4,308,061; 4,770,706; and 5,026,755, all incorporated hereinby reference.

The modified carbon products of the present invention, either as apredispersion or as a solid, can be incorporated into an aqueous inkformulation using standard techniques.

Flexographic inks represent a group of aqueous ink compositions.Flexographic inks generally include a colorant, a binder, and a solvent.The modified carbon products of the invention may be useful asflexographic ink colorants. The modified carbon products of theinvention may be used in aqueous news inks. For example, an aqueous newsink composition may comprise water, the modified carbon products of theinvention, a resin and conventional additives such as antifoam additivesor a surfactant.

The modified carbon products of this invention may also be used inaqueous coating compositions such as paints or finishes. Thus, anembodiment of the invention is an improved aqueous coating compositioncomprising water, resin and a modified carbon product according to theinvention. Other known aqueous coating additives may be incorporated theaqueous coating composition. See, for example, McGraw-Hill Encyclopediaof Science & Technology, 5th Ed. (McGraw-Hill, 1982), incorporatedherein by reference. See also U.S. Pat. Nos. 5,051,464, 5,319,044,5,204,404, 5,051,464, 4,692,481, 5,356,973, 5,314,945, 5,266,406, and5,266,361, all incorporated herein by reference. The modified carbonproducts of the invention, either as a predispersion or as a solid, canbe incorporated into an aqueous coating composition using standardtechniques.

An ink or coating may be used for a variety of applications. Preferably,in aqueous inks and coatings of the present invention, the modifiedcarbon products are present in an amount of less than or equal to 20% byweight of the ink or coating. It is also within the bounds of thepresent invention to use an aqueous or non-aqueous ink or coatingformulation containing a mixture of unmodified carbon with the modifiedcarbon products of the present invention. Common additives such as thosediscussed below may be added to the dispersion to further improve theproperties of the aqueous ink or coating.

Also, the modified carbon products of the present invention can be usedin ink jet inks where the ink formulation may be based on solvents,aqueous, or an aqueous emulsion.

The ink compositions of the present invention may be prepared utilizingconventional techniques known to those skilled in the art, such ascombining or mixing the desired components in suitable medium.Typically, the ink compositions are aqueous systems and include thereina signficant amount of water, preferably deionized or distilled water.For example, the amount of water or similar medium is generally presentin an amount ranging from about 60% to about 95%, preferably from about75% to about 90%, based on the weight of the ink composition.

Suitable additives are generally incorporated into the ink compositionsto impart a number of desired properties while maintaining the stabilityof the compositions. Such additives are well known in the art andinclude humectants, biocides, binders, drying accelerators, penetrants,surfactants, and the like. For example, a humectant may be added toreduce the rate of evaporation of water in the ink to minimizeprintehead nozzle clogging. If the ink begins to dry out, the humectantconcentration increases and evaporation decreases further. Humectantsmay also affect other properties of the ink and prints made therefrom,such as viscosity, pH, surface tension, optical density, and printquality. Such humectants typically include ethylene glycol, propyleneglycol, diethylene glycols, glycerine, dipropylene glycols, polyethyleneglycols, polypropylene glycols, alkane diols, amides, ethers, carboxylicacids, esters, alcohols, organosulfides, organosulfoxides, sulfones,alcohol derivatives, 3-pyrrolidone, ether derivatives, amino alcohols,and ketones. The amount of a particular additive will vary depending ona variety of factors including the molecular weight of the polymers, theviscosity, the amount of any ammonium salt added, as well as the natureof the polymers, the nature of any organic groups attached to thepigment, e.g., modified carbon black products.

Printed images may be generated from the ink compositions of the presentinvention by incorporating such compositions into a suitable printingapparatus, and generating an image onto a substrate. Suitable ink jetprinters include, for example, thermal printers, piezoelectric printers,continuous printers, valve jet printers and the like. Similarly, anysuitable substrate can be employed including plain papers, bondedpapers, coated papers, transparency materials, textile materials,plastics, polymeric films, inorganic substrates and the like.

Lastly, the present invention also relates to other non-aqueous ink andcoating formulations. In these formulations, an appropriate solvent ispresent along with a modified carbon product of the present invention.For these formulations, the modified carbon product comprises carbonhaving attached at least one organic group wherein the organic groupcomprises a) at least one aromatic group or a C₁ -C₁₂ alkyl group, andb) at least one ionic group, at least one ionizable group, or a mixtureof an ionic group and an ionizable group. The aromatic group is directlyattached to the carbon and there are no limits on the amount of organicgroup present on the carbon. The various additional ingredientsdescribed above with respect to the non-aqueous ink and coatingformulations applies equally here as well as the amounts of the variouscomponents except for the amount of organic group on the carbon whereinthere is no upper or lower limit. The above discussion regarding theorganic groups and examples thereof apply equally here.

The following examples are intended to illustrate, not limit, theclaimed invention.

BET Nitrogen surface areas were obtained using ASTM D-4820. CTAB areameasurements were obtained using ASTM D-3760. DBPA data were obtainedusing ASTM D-2414. Optical properties of the ink and coating films weredetermined with the following instruments: L*a*b* values with a HunterLab Scan 6000 at 10 degree D65 CIELAB color space instrument; opticaldensity was measured with a MacBeth RD918 densitometer; gloss wasmeasured with a BYK Gardner model 4527 glossmeter.

The nitrogen and external surface area (t-area) was measured followingthe sample preparation and measurement procedure described in ASTMD-3037. For this measurement the nitrogen adsorption isotherm isextended up to 0.55 relative pressure. The relative pressure is thepressure (P) divided by the saturation pressure (Po, the pressure atwhich the nitrogen condenses). The adsorption layer thickness (t inangstroms) was calculated using the relation:

    t=0.88(P/Po).sup.2 +6.45(P/Po)+2.98.

The volume (v) of nitrogen adsorbed was then plotted against t₁ and astraight line was then fitted through the data points for t valuesbetween 3.9 and 6.2 angstroms. The t-area was then obtained from theslope of this line as follows:

    t-area, m.sup.2 /g=15.47×slope.

Sulfur contents on the carbon black product were determined bycombustion analysis after Soxhlet washing of each sample. The mmolsulfur attached was determined by difference from the assay of theuntreated carbon black.

EXAMPLE 1 Preparation of a Carbon Black Product with a Diazonium SaltGenerated in situ

Sulfanilic acid (3.0 g) was added to 900 mL deionized water and themixture heated to 70°-90° C. To this solution was added a carbon blackwith a CTAB surface area of 350 m² /g, t-area of 366 m² /g, and a DBPAof 120 mL/100 g (100 g). This mixture was stirred well to wet out all ofthe carbon black. A solution of 1.2 g sodium nitrite in 1.0 mL deionizedwater was added to the carbon black slurry. Gas was evolved withinseveral minutes. Heating of the mixture was suspended and the mixtureallowed to cool to ambient temperature with continued stirring. Theproduct was isolated by evaporation of the solution in an oven at70°-100° C. The product had attached p-C₆ H₄ --SO₃ Na groups.

Alternatively, the product could be isolated by filtration of the slurryin a Buchner funnel and washing the solids with deionized water.

EXAMPLE 2 Preparation of Carbon Black Products having different amountsof attached groups

The procedure of Example 1 was repeated with a carbon black with a CTABsurface area of 350 m² /g, t-area of 366 m² /g, and a DBPA of 120 mL/100g using the amounts of reagents listed in the table below:

    ______________________________________                                        Example                                                                              Sulfanilic Acid (g)                                                                         g NaNO.sub.2 /g H.sub.2 O                                                                 Carbon Black (g)                             ______________________________________                                        2a     7.0           2.8/3       100                                          2b     15.0          6.0/6       100                                          ______________________________________                                    

EXAMPLE 3 Preparation of a Carbon Black Product Using a Pin Pelletizer

An eight inch diameter pin pelletizer was charged with 300 g of a carbonblack with a CTAB surface area of 350 m² /g, t-area of 366 m² /g, and aDBPA of 120 mL/100 g and 15 g sulfanilic acid. The pelletizer was run at150 rpm for 1 minute. A solution of deionized water (280 mL) and sodiumnitrite (5.98 g) were added and the pelletizer was run for 2 minutes at250 rpm. The pelletizer was stopped and the shaft and pins were scrapedoff, then the pelletizer was run at 650 rpm for an additional 3 minutes.The 4-sulfobenzenediazonium hydroxide inner salt was generated in situ,and it reacted with the carbon black. The product was discharged fromthe pelletizer and dried in an oven at 70°-100° C. The product hadattached p-C₆ H₄ --SO₃ Na groups. Analysis of a Soxhlet extracted samplefor sulfur content indicated that this product had 0.15 mequiv./gattached sulfonate groups, or 0.43 micromoles/m² of attached sulfonategroups.

EXAMPLE 4 Preparation of a Carbon Black Product

A solution of the diazonium salt of 4-aminosalicylic acid was preparedas follows. To 550 mL deionized water was added 57.4 g of4-aminosalicylic acid. The mixture was cooled in an ice bath and 93.75mL concentrated hydrochloric acid was added. To this cold mixture wasadded a solution of 25.9 g sodium nitrite in 50 mL deionized water. Themixture darkened in color and some gas was released. This solution wascalculated to contain 0.038 g of the diazonium of 4-aminosalicylicacid/g solution.

To a well stirred slurry of a carbon black with a CTAB surface area of350 m² /g and a DBPA of 120 mL/100 g (200 g) in 1.8 L deionized watercooled in an ice bath was added 233.2 g of the 4-aminosalicylicdiazonium solution. Gas was evolved. Stirring was continued until nofurther gas evolution was observed. The slurry was vacuum filtered andwashed with deionized water. The wet cake was dried in an oven at 75° C.The product had attached p-C₆ H₃ --(2--OH)--COOH groups.

EXAMPLE 5 Preparation of a Carbon Black Product

To a well stirred slurry of a carbon black with a CTAB surface area of350 m² /g and a DBPA of 120 mL/100 g (200 g) in 1.8 L deionized watercooled in an ice bath was added 1168 g of the 4-aminosalicylic diazoniumsolution as prepared in Example 4. Gas was evolved. Stirring wascontinued until no further gas evolution was observed. The slurry wasvacuum filtered and washed with deionized water. The wet cake was driedin an oven at 75° C. The product had attached p-C₆ H₃ --(2--OH)--COOHgroups.

EXAMPLE 6 Preparation of a Carbon Black Product

A solution of the diazonium salt of 4-aminobenzoic acid was prepared asfollows. To 925 mL deionized water was added 89.1 g of 4-aminobenzoicacid. The mixture was cooled in an ice bath and 162.5 mL concentratedhydrochloric acid was added. Acetone (50 mL) was added to completelydissolve the 4-aminobenzoic acid. To this cold mixture was added asolution of 44.9 g sodium nitrite in 100 mL deionized water. The mixturedarkened in color and some gas was released. This solution wascalculated to contain 0.061 g of the diazonium of 4-aminobenzoic acid/gsolution.

To a well stirred slurry of a carbon black with a CTAB surface area of350 m² /g and a DBPA of 120 mL/100 g (200 g) in 1.8 L deionized watercooled in an ice bath was added 131 g of the 4-aminobenzoic diazoniumsolution. Gas was evolved. Stirring was continued until no further gasevolution was observed. The slurry was vacuum filtered and washed withdeionized water. The wet cake was dried in an oven at 75° C. The producthad attached p-C₆ H₄ --COOH groups. The product had a 325 mesh residueof 90%.

EXAMPLE 7 Preparation of Carbon Black Products having different amountsof attached groups

Using the Diazonium solution prepared in Example 6, a carbon black witha CTAB surface area of 350 m² /g and a DBPA of 120 mL/100 g wasfunctionalized with various amounts of the phenyl carboxylate group. Theamounts used are presented in the table below. The procedure used wasanalogous to Example 6.

    ______________________________________                                               Amount of      Amount of  325 Mesh                                     Example                                                                              Diazonium Solution                                                                           Carbon Black                                                                             Residue                                      ______________________________________                                        7a     263 g          200 g      63.7%                                        7b     394 g          200 g      3.9%                                         7c     656 g          200 g      4.0%                                         ______________________________________                                    

EXAMPLE 8 Preparation of a Carbon Black Product in a Pin Pelletizer

This process was analogous to Example 3 using 300 g of a carbon blackwith a CTAB surface area of 350 m² /g and a DBPA of 120 mL/100 g and 24g of 4-aminobenzoic acid. The pelletizer was run at 500 rpm for 1minute. A solution of deionized water (300 mL) and sodium nitrite (12.1g) were added and the pelletizer was run for 2-3 minutes at 1100 rpm.The product was discharged from the pelletizer and dried in an oven at70°-100° C. The product had attached p-C₆ H₄ --COONa groups.

EXAMPLE 9 Preparation of a Carbon Black Product

This represents an alternative method for producing a product like thatof Example 6. The product of Example 8 (150 g) was slurried in 500 mLdeionized water. To this slurry was added 21.9 mL concentratedhydrochloric acid. After stirring 30 minutes, the slurry was filteredand washed with deionized water, and the wet cake was dried at 75° C.The product had attached p-C₆ H₄ --COOH groups.

EXAMPLE 10 Preparation of a Carbon Black Product

This procedure is analogous to Example 1, except an oxidized carbonblack with a nitrogen surface area of 560 m² /g, a DBPA of 90 mL/100 g,and a volatile content of 9.5% was used. Amounts of reagents used foreach treatment level are shown in the table below. Carbon black was a10% slurry in deionized water.

    ______________________________________                                               Sulfanilic                                                                             g NaNO.sub.2 /g                                                                          Carbon mmol S attached/g                           Example                                                                              Acid (g) H.sub.2 O  Black (g)                                                                            Product                                     ______________________________________                                        10a    6.0      2.4/3      200    0.162                                       10b    10.0     4.0/5      200    0.237                                       10c    20.0     8.0/8      200    0.496                                       10d    30.0     12.0/12    200    0.670                                       10e    50.0     19.0/20    200    1.00                                        ______________________________________                                    

EXAMPLE 11 Preparation of a Carbon Black Product

The procedure of Example 3 was used where the carbon black had a t-areaof 93 m² /g and a DBPA of 55 mL/100 g. The amount of reagents used areshown in the table below.

    __________________________________________________________________________                         Deionized                                                                          mmol S                                                                             μmol S                                      Carbon from                                                                         Carbon                                                                             Sulfanilic                                                                         NaNO.sub.2                                                                         Water                                                                              attached/g                                                                         attached/m.sup.2                               Example #                                                                           Black (g)                                                                          Acid (g)                                                                           (g)  (mL) Product                                                                            Product                                        __________________________________________________________________________    11a   400  0    0    215  0    0                                              11b   400  4    1.6  215  0.041                                                                              0.44                                           11c   400  8    3.2  215  0.084                                                                              0.90                                           11d   400  20   8.0  215  0.193                                                                              2.08                                           __________________________________________________________________________

These products have attached p-C₆ H₄ --SO₃ Na groups. Samples of eachwere Soxhlet extracted (ethanol) and analyzed for sulfur content.Results are shown in the table along with the corresponding amount ofattachment/m².

The pellets produced from this process were ground in an 8-inch jet mill(Sturtevant, Boston, Mass.) to convert the pellets to a "fluffy" typeproduct. This process is described in Perry's Chemical Engineers'Handbook," 6th Ed., R. H. Perry and D. Green, Eds., pp. 8-46. Theseground materials were used in Example 18.

EXAMPLE 12 Preparation of a Carbon Black Product

This procedure describes the preparation of a carbon black product undercontinuous operating conditions. 100 parts per hour of a carbon blackhaving a CTAB surface area of 350 m² /g and a DBPA of 120 mL/100 g wascharged to a continuously operating pin mixer with 25 parts per hour ofsulfanilic acid and 10 parts per hour of sodium nitrite as an aqueoussolution. The resultant material was dried to give a carbon blackproduct having attached p-C₆ H₄ SO₃ Na groups. Analysis of a Soxhletextracted (ethanol) sample for sulfur content indicated that the producthad 0.95 mequiv./g attached sulfonate groups, or 2.7 micromoles/m²attached sulfonate groups.

EXAMPLE 13 Use of Carbon Black Products in Coating Compositions

This example illustrates the use of carbon black products in thermosetacrylic compositions. The standard was a carbon black with a CTABsurface area of 350 m² /g and a DBPA of 120 mL/100 g without anyadditional treatments. The materials evaluated here were prepared inExamples 1, 2a, 2b, and 12.

The coating compositions were prepared as follows. To each one halfgallon steel ball mill were charged: 2.1 kg 1/4" steel balls, 3.3 kg1/2" steel balls, 282 g grind masterbatch (64 parts ACRYLOID AT400resin, 30 parts n-butanol, 6 parts methyl-n-amyl ketone), and 30 gcarbon black. The mill jars were turned at 44 rpm on a jar rolling milloperating at 82 rpm (Paul O. Abbe model 96806 or equivalent) for thetime indicated. The finished coating formulation was prepared by firstreducing each mill with 249 g AT-400 resin and turning for one hour onthe jar mill. A second reduction was done by adding 304 g of a mixtureof 33 parts AT-400 resin, 35.3 parts CYMEL 303 melamine-formaldehyderesin, 7.2 parts methyl-n-amyl ketone, 8.5 parts 2-ethoxyethyl acetate,1.8 parts CYCAT 4040 (an acid catalyst of toluenesulfonic acid andisopropanol), 0.3 parts FLUORAD FC431 additive, 14 parts n-butanol, androlling for one hour.

ACRYLOID is a registered trademark for resins available from Rohm andHaas, Philadelphia, Pa.; CYMEL and CYCAT are registered trademarks forproducts available from Cytec Industries, West Patterson, N.J.; andFLUORAD is a registered trademark for additives available from 3M, St.Paul, Minn.

The optical properties were determined on a 3 mil film on a sealedLeneta chart that had been air dried for 30 minutes and then baked at250° C. for 30 minutes. A Hunter Color Meter was used to measure L*, a*,and b* values. Optical density was measured with a MacBeth RD918densitometer. Gloss was measured with a BYK Gardner model 4527glossmeter. Viscosity was measured in Krebs Units on a Brookfield KU-1viscometer.

Thermoset acrylic formulations were prepared according to the generalmethod described by grinding in a ball mill for 27 hours. Draw downs, 3mil thick, were prepared and their optical properties were evaluated.The results are summarized in the following table:

    ______________________________________                                        Carbon from                                                                           Optical                     Gloss                                     Example #                                                                             Density L*      a*    b*    (60°)                                                                        Viscosity                           ______________________________________                                        Standard                                                                              2.76    1.55    0.02  0.02  89.9  107                                  1      2.81    1.29    -0.05 -0.12 92.0  105                                  2a     2.75    1.44    0.03  -0.06 90.0  98                                   2b     2.71    1.46    -0.06 0.15  87.5  91                                  12      2.77    1.40    0.02  0.12  81.3  82                                  ______________________________________                                    

There is a drop in formulation viscosity as treatment level isincreased. All optical properties peak at the lower levels; the coatingproduced using the carbon black product from Example 1, treated with 3wt % sulfanilic acid diazonium salt is more optically dense, jetter,bluer, and glossier than all the other materials. These samples areweight compensated for the treatment, i.e., the same weight of carbonblack in each formulation.

EXAMPLE 14 Carbon Black Products Functionalized with Various Levels ofSalicyclic Acid Used in a Thermoset Acrylic Formulation

Carbon black products prepared in Examples 4 and 5 were evaluated in athermoset acrylic formulation according to general method in Example 13after grinding for 18 and 42 hours. The results are summarized in thetable below. In this example, equal weights of carbon black product wereused in each formulation. The standard was carbon black with a CTABsurface area of 350 m² /g and a DBPA of 120 mL/100 g without anyadditional treatments.

    ______________________________________                                        Carbon                                                                        From   Grinding Optical                Gloss                                  Example #                                                                            Time (h) Density L*   a*   b*   (60°)                                                                       Viscosity                         ______________________________________                                        Standard                                                                             18       2.82    1.35 -0.15                                                                              0.03 93.0 93                                Standard                                                                             42       2.82    1.24 -0.07                                                                              -0.27                                                                              91.2 101                               4      18       2.87    1.16 -0.14                                                                              -0.16                                                                              93.7 97                                4      42       2.94    1.02 -0.04                                                                              -0.41                                                                              92.8 103                               5      18       2.85    1.25 -0.16                                                                              -0.18                                                                              92.2 94                                5      42       2.86    1.10 0.03 -0.36                                                                              92.5 98                                ______________________________________                                    

At each grinding time the material with the lower treatment, Example 4,shows greater optical density, jetness (L*), deeper bluetone, and moregloss than either the untreated standard or the more highly treatedmaterials from Example 5.

EXAMPLE 15 Carbon Black Product Treated with Various Levels of4-Aminobenzoic Acid Used in a Thermoset Acrylic Formulation

Carbon black products prepared according to Examples 6, 7a, and 7b wereevaluated in a thermoset acrylic formulation, as described in Example13. The optical properties of a coating prepared after 27 hours ofgrinding are shown in the Table below. Each formulation contained 30 gof the carbon black product. The standard was carbon black with a CTABsurface area of 350 m² /g and a DBPA of 120 mL/100 g without anyadditional treatments.

    ______________________________________                                        Carbon                                                                        from    Optical                     Gloss                                     Example #                                                                             Density L*      a*    b*    (60°)                                                                        Viscosity                           ______________________________________                                        Standard**                                                                            2.82    1.58    -0.06 0.17  91.6  94                                  6       3.09    0.88    -0.15 -0.26 91.7  100                                 7a      3.19    0.75    -0.04 -0.22 96.5  91                                  7b      3.22    0.75    -0.06 -0.22 98.0  88                                  7c      3.20    0.74    -0.10 -0.20 98.4  85                                  ______________________________________                                         **Sample prepared after 42 hours grinding.                               

In this example with attached benzoic acid groups, Example 7a, treatedwith 8 wt % 4-aminobenzoic acid diazonium salt, is sufficient to giveimproved optical properties over the standard, untreated, carbon black.Higher treatment levels did not improve the coating propertiessignificantly.

EXAMPLE 16 Performance of a Surface Treated Carbon Black Product FurtherFunctionalized with Various Amounts of Sulfanilic Acid Diazonium Salt

Carbon Black products prepared in Examples 10a-e (3, 5, 10, 15, 25 wt %sulfanilic acid diazonium, respectively) were evaluated in a thermosetacrylic formulation, as described in Example 13. The optical propertiesof a coating prepared after 27 hours grinding are shown in the tablebelow. Each formulation contained an equal amount of carbon blackproduct. The standard was a surface treated carbon black with a nitrogensurface area of 560 m² /g, a DBPA of 90 mL/100 g, and a volatile contentof 9.5%.

    ______________________________________                                        Carbon                                                                        from    Optical                     Gloss                                     Example #                                                                             Density L*      a*    b*    (60°)                                                                        Viscosity                           ______________________________________                                        Standard                                                                              2.68    1.74    -0.07 0.11  88.8  92                                  10a     2.95    1.32    -0.01 0.14  93.7  89                                  10b     2.88    1.12    -0.11 -0.19 86.5  98                                  10c     2.84    1.21    -0.08 -0.10 76.9  102                                 10d     2.85    1.24    -0.07 -0.06 84.0  99                                  10e     2.81    1.34    -0.03 0.08  90.1  97                                  ______________________________________                                    

Oxidized carbon black products with attached sulfonate acid groups havegreater optical densities, jetness, and bluer undertone than anuntreated standard. Example 10b (5 wt % treatment) was jetter and bluerthan the other materials.

EXAMPLE 17 Carbon Black Product Treated With Various Levels ofSulfanilic Acid Used in a Urethane Hardened Acrylic Formulation

This example illustrates the use of carbon black products in an acrylicenamel formulation. Carbon black products from Examples 3 and 12 wereused in the following composition. The carbon black products were groundin small steel mills (21/16" tall ×23/32" diameter) on a paint shaker.Each mill was charged with 200 g 3/16" chrome steel balls, 2.19 g carbonproduct, and 19.9 g of grind vehicle consisting of an 80/20 mixture ofDMR-499 acrylic mixing enamel (PPG Finishes, Strongsville, Ohio) andxylene. This mixture was ground for 50 minutes. Samples were evaluatedon a Hegman gauge. The final formulation was made by adding 23.3 gDMR-499, 17.3 g xylene and 1.4 g DXR-80 urethane hardener (PPG Finishes,Strongsville, Ohio) to the mill and shaking for 15 minutes. A 3 mildrawdown of the completed formulation was made on a sealed Leneta chart.The film was air dried for 30 minutes, then baked at 140° F. for 30minutes. Optical properties were determined as described in Example 13.

The standard was a carbon black with a CTAB surface area of 350 m² /gand a DBPA of 120 mL/100 g without any additional treatments. Opticalproperties and Hegman grinds are shown in the table below. Hegman valueswere measured on a Hegman gauge where 5 "sand" particles are clustered.

    ______________________________________                                        Carbon                                    Hegman                              from    Optical                     Gloss Grind at                            Example #                                                                             Density  L*     a*    b*    (60°)                                                                        50 min.                             ______________________________________                                        Standard                                                                              2.83     1.23   0.08  0.05  52.3  4.0                                  3      3.08     0.70   -0.04 -0.27 88.0  6.6                                 12      2.79     1.41   0.17  -0.03 92.5  6.2                                 ______________________________________                                    

In this formulation, wetting of the standard product was incomplete, asevidenced by the very low gloss and Hegman gauge readings. The carbonfrom Example 12 was weight compensated for the amount of treatment onthe carbon (2.66 g). The product of Example 3 (5 wt % sulfanilic aciddiazonium salt treatment) showed better optical density, jetness, andbluetone values compared to both the standard and the more highlytreated materials.

EXAMPLE 18 Evaluation of Carbon Black Products in a Gloss InkFormulation

The carbon black products of Examples 11a-11c were evaluated in astandard heat set gloss ink formulation prepared on a three roll mill.Their performance was compared to an untreated standard, a carbon blackwith a surface area of 90 m² /g and a DBPA of 55 mL/100 g.

The carbon black samples were prepared for grind on a three roll mill byhand mixing 15 g of the carbon black with 35 g of the grind masterbatch.The masterbatch consists of 9 parts LV-3427XL (heatset grinding vehicle,Lawter International, Northbrook, Ill.), to 1 part MAGIESOL 47 oil. Thismixture, 50 g, was ground on a Kent three roll mill running at 70° F.Samples were let down by mixing with an equal amount of grindmasterbatch and then applied to a NIPRI production grindometer G-2 forevaluation of the grind. The standards were typically passed four timesthrough the mill. Additional passes were made if the grind gauge readingwas above 20 microns. The finished ink was produced by mixing the milledmaterial with an equal weight of letdown masterbatch (3 parts LV3427XL,12 parts LV6025 (heatset gel vehicle, Lawter International), 5 partsMAGIESOL 47 oil) and passing one time through the three roll mill.

MAGIESOL is a registered trademark for oils available from MagieBrothers, Franklin Park, Ill.

Fineness of grind data and viscosity measurements of the resulting inksare shown in the table below. The values in the grind data table are inmicrons as measured on a G-2 grind gauge and indicate the level where 10scratches/5 scratches/5 defect grains are detected on the gauge. Steelbar Laray viscosity was measured according to ASTM method D4040-91 at25° C. using a TMI 95-15-00 Laray viscometer (Testing Machines Inc.),vertical glass plate flow was measured by the distance a 0.5 cc sampleof ink travels down a vertical glass plate after the samples are allowedto rest for 0, 30, and 60 minutes prior to standing the plate, andspreadometer properties were measured using a Toyoseiki spreadometer(Testing Machines Inc.) as described in Japanese Industrial Standard,Testing Methods for Lithographic and Letterpress Inks (JIS K5701-4.1.2).

    ______________________________________                                        Properties/Sample                                                                              11a     11b     11c   11d                                    ______________________________________                                        Carbon Black Properties                                                       Ink Preparation                                                               Grinding Base (5 scr/10 scr/sand)                                             Three roll mill                                                               1 pass           6/0/46  0/0/27  0/0/24                                                                              0/0/24                                 2 passes         0/0/40  0/0/14  0/0/22                                                                              0/0/20                                 3 passes         0/0/20  0/0/13  0/0/12                                                                              0/0/17                                 4 passes         0/0/16  0/0/12  0/0/12                                                                              0/0/18                                 Ink Properties                                                                Steel Bar Laray Viscosity                                                     Viscosity (poise at 2500 s.sup.-1)                                                             66.7    64.6    61.7  58.2                                   Yield Value (dyne/cm at 2.5 s.sup.-1)                                                          507     553     533   490                                    Vertical Glass Plate Flow (mm)                                                No Setting                                                                    20 minutes       85      125     105   115                                    40 minutes       95      155     132   144                                    60 minutes       105     175     145   167                                    30 Minutes Setting                                                            20 minutes       43      98      85    95                                     40 minutes       56      126     109   119                                    60 minutes       61      145     126   139                                    60 Minutes Setting                                                            20 minutes       26      95      79    86                                     40 minutes       42      125     102   115                                    60 minutes       48      143     120   135                                    Spreadometer Properties                                                       Slope (mm)       8.6     9.8     9.3   9.2                                    Intercepter (mm) 23.9    23.3    24.9  25.6                                   Yield Value (dyne/cm.sup.2)                                                                    128.4   113.3   116.0 114.1                                  ______________________________________                                    

These data demonstrate how the treatment modifies the rheology of theink formulation. In these cases, increasing the treatment level reducedthe Laray viscosity slightly, but significantly increased the flow(vertical glass plate flow). That the flow remains high after the onehour setting time indicates that this ink composition will flow moreconsistently over time. This is particularly valuable in offset ink.

The spreadometer slope is also an indication of flowability, but underdifferent shear conditions (higher values correspond to greater flow).The spreadometer intercepter is an indication of the sample's plasticviscosity.

Optical properties for inks made from the carbon black products 11a-11cand the standard carbon black were determined from prints made using anRNA-42 printability tester (Research North America Inc.) and are shownin the table below. Values for 1.0 and 2.0 micron film thicknesses werecalculated from regression of the data from the prints made over a rangeof film thicknesses.

    ______________________________________                                        Optical Properties of a 1 Micron Film Made From Samples 11a-d                 Example  OD       L*     a*     b*   Gloss 60°                         ______________________________________                                        11a      1.47     19.9   1.94   5.87 45.3                                     11b      1.37     23.23  1.93   6.18 45.1                                     11c      1.38     23.67  1.79   5.72 42.3                                     11d      1.20     31.10  1.63   5.84 38.6                                     ______________________________________                                    

    ______________________________________                                        Optical Properties of a 2 Micron Film Made From Samples 11a-d                 Example  OD       L*     a*     b*   Gloss 60°                         ______________________________________                                        11a      2.28     2.93   0.68   0.75 49.1                                     11b      2.24     3.16   0.94   1.33 46.8                                     11c      2.08     5.41   1.53   2.67 48.1                                     11d      2.10     4.30   0.95   1.39 39.7                                     ______________________________________                                    

These data indicate that increasing treatment levels diminish theoptical properties somewhat. Example 11b combines the improved rheology(for offset ink application) and very good dispersion with a minimum ofloss of the optical properties. Since equal sample weights were used inthis study, some of the loss in jetness may be due to the relativelylower amounts of black used as the treatment levels are increased.

EXAMPLE 19 Preparation of a Carbon Black Product

The procedure of Example 12 was repeated except that 100 parts of acarbon black having a nitrogen specific surface area of 200 m² /g and aDBPA of 120 mL/100 g, 12.5 parts sulfanilic acid, 5 parts sodium nitriteas an aqueous solution, and 110 parts deionized water was used. The rateof the pin pelletizer was 100 pounds per hour. The resultant product hadattached pC₆ H₄ --SO₃ ⁻ Na⁺ groups.

EXAMPLE 20 Preparation of a Carbon Black Products Having DifferentAmounts of Attached Groups

The procedure of Example 19 was repeated with a carbon black with anitrogen specific surface area of 200 m² /g and a DBPA of 120 mL/100 gexcept using the amounts of reagents listed in the table below:

    ______________________________________                                               Sulfanilic Acid                                                                          NaNO.sub.2                                                                             Carbon Black                                                                           Deionized H.sub.2 O                       Example                                                                              (parts)    (parts)  (parts)  (parts)                                   ______________________________________                                        20a    6.0        2.4      100      110                                       20b    9.0        3.6      100      110                                       ______________________________________                                    

EXAMPLE 21 Preparation of a Carbon Black Product

The procedure of Example 19 was repeated using a carbon black with anitrogen specific surface area of 200 m² eg and a DBPA of 120 mL/100 gexcept using 14 parts p-aminobenzoic acid, 100 parts carbon black, 7parts sodium nitrite as an aqueous solution, and 110 parts deionizedwater. The rate of the pin pelletizer was 100 pounds per hour. Theresultant product had attached pC₆ H₄ --CO₂ ⁻ Na⁺ groups.

EXAMPLE 22 Preparation of a Carbon Black Product Having DifferentAmounts of Attached Groups

The procedure of Example 21 was repeated with a carbon black with anitrogen specific surface area of 200 m² /g and a DBPA of 120 mL/100 gexcept using the amounts of reagents listed in the table below:

    ______________________________________                                               p-Amino-benzoic                                                                           NaNO.sub.2                                                                            Carbon Black                                                                           Deionized H.sub.2 O                       Example                                                                              Acid (parts)                                                                              (parts) (parts)  (parts)                                   ______________________________________                                        22a    9.0         4.5     100      110                                       22b    11.0        5.5     100      110                                       ______________________________________                                    

EXAMPLE 23 Preparation of a Carbon Black Product

The procedure of Example 1 was repeated except that 100 g carbon blackhad a nitrogen specific surface area of 140 m² /g and a DBPA of 116mL/100 g, 10.72 g of N-(4-aminophenyl) pyridinium nitrite, 25 mL of a 2M/L nitric acid solution, and 500 g of distilled water. The resultantproduct had attached C₅ H₄ N⁺ (NO₃)--C₆ H₅ groups.

EXAMPLE 24 Preparation of a Carbon Black Product Having DifferentAmounts of Attached Groups

The procedure of Example 23 was repeated using a carbon black with anitrogen specific surface area of 140 m² /g and a DBPA of 116 mL/100 gexcept using the amounts of reagents listed in the table below.

    ______________________________________                                               N-(4-amino phenyl)                                                                          2 M/L HNO.sub.3                                                                         Carbon Distilled                               Example                                                                              pyrindinium nitrite (g)                                                                     (mL)      Black (g)                                                                            H.sub.2 O (g)                           ______________________________________                                        24a    8.58          20        100    500                                     24b    6.43          15        100    500                                     ______________________________________                                    

EXAMPLE 25 Evaluation of a Carbon Black Product in an Ink Jet InkFormulation Composition

The carbon black products of Examples 19 and 20 were dispersed into10-20% (w/w) slurries with distilled water and filtered to less than 1micron in diameter. The dispersions were then formulated into ink jetinks, with the resulting black pigment concentration of 5%, 10%2-pyrrilondone, 10% pentanediol, and 75% distilled water (Formulation1).

The inks were placed into emptied and cleaned ink jet cartridges andprinted with Hewlett-Packard DeskJet 660 printer on Gilbert® 25%cotton-20 lb. paper having an optical density of 0.10, Champion® Ink JetSoft Bright White 20 lb. paper having an optical density of 0.11,Hammermill® Fore® DP Long Grain paper having an optical density of 0.12,and Xerox 4024 DP 20 lb. paper having an optical density of 0.10. Theresulting print properties of optical density and waterfastness overtime were measured and compared below.

The optical density was measured using a MACBETH RD-915 densitometerfrom Macbeth, New Windsor, N.Y. following ANSI procedure CGATS, 4-1993(MACBETH is a registered trademark of Kollmorgen InstrumentsCorporation).

The following procedure was utilized to determine waterfastness. Theprinted image was placed on a stand at 45° angle. A calibrated pipettewas used to dispense 0.25 mL of distilled water over the image at fiveminutes after printing, one hour after printing, and two hours afterprinting. The water produced a run-off portion from the image. Thewaterfastness, in this case a measurement of the true wash-off of theimage, was determined by subtracting the optical density of the paperfrom the optical density of the run-off portion of the image.

    __________________________________________________________________________    Example in  Print Optical Density on Various Papers                           Formulation 1                                                                             Gilbert                                                                           Champion  Hammermill                                                                          Xerox                                         __________________________________________________________________________    19          1.34                                                                              1.36      1.33  1.35                                          20a         1.51                                                                              1.40      1.47  1.51                                          20b         1.61                                                                              1.56      1.57  1.56                                          __________________________________________________________________________    Print Wash-Off Optical Density Over Time on Various Papers                    Gilbert       Champion Hammermill                                                                             Xerox                                         Example                                                                            5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                    __________________________________________________________________________    19   0.40                                                                             0.44                                                                             0.40                                                                             0.52                                                                             0.51                                                                             0.41                                                                             0.19                                                                             0.19                                                                             0.17                                                                             0.38                                                                             0.45                                                                             0.36                                    20a  0.05                                                                             0.05                                                                             0.04                                                                             0.43                                                                             0.43                                                                             0.33                                                                             0.01                                                                             0.00                                                                             0.00                                                                             0.15                                                                             0.03                                                                             0.02                                    20b  0.44                                                                             0.40                                                                             0.25                                                                             0.52                                                                             0.65                                                                             0.71                                                                             0.35                                                                             0.25                                                                             0.18                                                                             0.42                                                                             0.40                                                                             0.46                                    __________________________________________________________________________

No noticeable print runoff was observed at <0.20 optical density units.The data showed the optical density was highest for the print containingExample 20b, while the print that was most waterfast was made withExample 20a. As illustrated, the print optical density and waterfastnesswere both influenced by the amount and type of groups that are on thecarbon black, and an optimum amount of groups may be added to the carbonblack for the desired print property. Also, print properties can bedependent upon properties of the ink jet ink formulation, the printer,and the paper or substrate.

EXAMPLE 26 Evaluation of a Carbon Black Product in an Ink Jet InkFormulation

The carbon black products of Examples 21 and 22 were prepared andincorporated into the same ink formulations as in Example 25 with theresults shown below. The data showed that as the amount of added groupson the carbon black pigment decreased, the waterfastness of the printedimage, as determined by the method described in Example 25, improved.The prints made with Example 22a were more waterfast and generallydarker (higher o.d.) then those made with the other examples usingFormulation 1.

    __________________________________________________________________________    Example in  Print Optical Density on Various Papers                           Formulation 1                                                                             Gilbert                                                                           Champion  Hammermill                                                                          Xerox                                         __________________________________________________________________________    21          1.46                                                                              1.43      1.52  1.48                                          22a         1.56                                                                              1.57      1.58  1.60                                          22b         1.54                                                                              1.55      1.61  1.57                                          __________________________________________________________________________    Print Wash-Off Optical Density Over Time on Various Papers                    Gilbert       Champion Hammermill                                                                             Xerox                                         Example                                                                            5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                    __________________________________________________________________________    21   0.04                                                                             0.04                                                                             0.03                                                                             0.50                                                                             0.40                                                                             0.47                                                                             0.04                                                                             0.02                                                                             0.02                                                                             0.06                                                                             0.02                                                                             0.02                                    22a  0.00                                                                             0.01                                                                             0.02                                                                             0.27                                                                             0.16                                                                             0.14                                                                             0.01                                                                             0.02                                                                             0.00                                                                             0.00                                                                             0.00                                                                             0.00                                    22b  0.04                                                                             0.02                                                                             0.02                                                                             0.47                                                                             0.39                                                                             0.41                                                                             0.01                                                                             0.01                                                                             0.01                                                                             0.04                                                                             0.01                                                                             0.01                                    __________________________________________________________________________

EXAMPLE 27 Evaluation of a Carbon Black Product in an Ink Jet InkFormulation

The carbon black products of Examples 23 and 24 were prepared andincorporated into the same ink formulations as Example 25 with theresults shown below. The data showed that the print with the highestoptical density was made with Example 23, while the same print was lesswaterfast on some papers compared to the other samples. As shown, printsmade with a positively-charged carbon black were very waterfast on mostpapers.

    __________________________________________________________________________    Example in  Print Optical Density on Various Papers                           Formulation 1                                                                             Gilbert                                                                           Champion  Hammermill                                                                          Xerox                                         __________________________________________________________________________    23          1.47                                                                              1.40      1.47  1.47                                          24a         1.43                                                                              1.40      1.46  1.41                                          24b         1.27                                                                              1.26      1.33  1.33                                          __________________________________________________________________________    Print Wash-Off Optical Density Over Time on Various Papers                    Gilbert       Champion Hammermill                                                                             Xerox                                         Example                                                                            5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                                                             5 min                                                                            1 hr                                                                             2 hr                                    __________________________________________________________________________    23   0.08                                                                             0.04                                                                             0.02                                                                             0.26                                                                             0.13                                                                             0.07                                                                             0.01                                                                             0.01                                                                             0.00                                                                             0.01                                                                             0.01                                                                             0.00                                    24a  0.02                                                                             0.02                                                                             0.01                                                                             0.06                                                                             0.05                                                                             0.05                                                                             0.01                                                                             0.00                                                                             0.01                                                                             0.00                                                                             0.01                                                                             0.00                                    24b  0.01                                                                             0.00                                                                             0.00                                                                             0.03                                                                             0.03                                                                             0.03                                                                             0.00                                                                             0.00                                                                             0.02                                                                             0.02                                                                             0.01                                                                             0.01                                    __________________________________________________________________________

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. It is intended that the specificationand examples be considered as exemplary only, with a true scope andspirit of the invention being indicated by the following claims.

What is claimed is:
 1. An ink jet ink composition comprising 1) anaqueous vehicle and 2) a modified carbon product comprising carbonhaving attached at least one organic group, the organic group comprisinga) at least one aromatic group or a C₁ -C₁₂ alkyl group, and b) at leastone ionic group, at least one ionizable group, or a mixture of an ionicgroup and an ionizable group, wherein the at least one aromatic group orC₁ -C₁₂ alkyl group of the organic group is directly attached to thecarbon and the organic group is present at a level of from about 0.10 toabout 4.0 micromoles/m² of the carbon used based nitrogen surface areaof the carbon.
 2. The composition of claim 1, wherein levels of theorganic group are from about 1.5 to about 3.0 micromoles/m² of thecarbon used based on nitrogen surface area of the carbon.
 3. Thecomposition of claim 1, wherein the ionic or the ionizable group is acarboxylic acid or a salt thereof.
 4. The composition of claim 1,wherein the ionic or the ionizable group is a sulfonic acid or a saltthereof.
 5. The composition of claim 1, wherein the organic group is asulfophenyl group or a salt thereof.
 6. The composition of claim 1,wherein the organic group is p-sulfophenyl or a salt thereof.
 7. Thecomposition of claim 1, wherein the organic group is p--C₆ H₄ SO₃ Na. 8.The composition of claim 1, wherein the organic group is a carboxyphenylgroup or a salt thereof.
 9. The composition of claim 1, wherein theorganic group is a p-carboxyphenyl group or a salt thereof.
 10. Thecomposition of claim 1, wherein the organic group is a p--C₆ H₄ CO₂ Hgroup.
 11. The composition of claim 1 wherein the ionic or the ionizablegroup is a quaternary ammonium salt.
 12. The composition of claim 1,wherein the organic group is 3-C₅ H₄ N(C₂ H₅)⁺ X⁻ ; C₆ H₄ NC₅ H₅ ⁺ X⁻,C₆ H₄ COCH₂ N(CH₃)₃ ⁺ X⁻, C₆ H₄ COCH₂ (NC₅ H₅)⁺ X⁻, 3-C₅ H₄ N(CH₃)⁺ X⁻,C₆ H₄ N(CH₃)₃ ⁺ X⁻, and C₆ H₄ CH₂ N(CH₃)₃ ⁺ X⁻, wherein X⁻ is a halideor an anion derived from a mineral or organic acid.
 13. The compositionof claim 1, wherein the organic group is pC₆ H₄ --SO₃ --Na⁺, pC₆ H₄--CO₂ --Na⁺, or C₅ H₄ N⁺ (NO₃)⁻ --C₆ H₅.
 14. The composition of claim 1,wherein the organic group is a carboxy-hydroxy phenyl group or its salt.15. The composition of claim 1, wherein the organic group is 4-carboxy-3hydroxy phenyl.
 16. The composition of claim 1, wherein the carbon iscarbon black, graphite, carbon fiber, vitreous carbon, finely-dividedcarbon, activated charcoal, activated carbon, or mixtures thereof. 17.The composition of claim 16, wherein the carbon is carbon black.
 18. Thecomposition of claim 1, wherein the aromatic ring of the aromatic groupis an aryl group.
 19. The composition of claim 1, wherein the aromaticring of the aromatic group is a heteroaryl group.
 20. The composition ofclaim 1, wherein the organic group has one or more groups selected fromR, OR, COR, COOR, OCOR, halogen, CN, NR₂, SO₂ NR(COR), SO₂ NR₂, NR(COR),CONR₂, NO₂, SO₃ M, SO₃ NR₄, and N═NR'; wherein R is independentlyhydrogen, C₁ -C₂₀ substituted or unsubstituted alkyl, C₃ -C₂₀substituted or unsubstituted alkenyl, (C₂ -C₄ alkyleneoxy)_(x) R", or asubstituted or unsubstituted aryl; R' is independently hydrogen, C₁ -C₂₀substituted or unsubstituted allyl, or a substituted or unsubstitutedaryl; R" is hydrogen, a C₁ -C₂₀ substituted or unsubstituted alkyl, a C₃-C₂₀ substituted or unsubstituted alkenyl, a C₁ -C₂₀ substituted orunsubstituted alkanoyl, or a substituted or unsubstituted aroyl; M is H,Li, Na, Cs, or K; and x is an integer ranging from 1-40.
 21. Thecomposition of claim 1 wherein the modified carbon product has furtherattached to the carbon an aromatic group of the formula A_(y) Ar--, inwhichAr is an aromatic radical selected from the group consisting ofphenyl, naphthyl, anthracenyl, phenanthrenyl, biphenyl, pyridinyl andtriazinyl; A is hydrogen, a functional group selected from the groupconsisting of R, OR, COR, COOR, OCOR, halogen, CN, NR₂, SO₂ NR₂, SO₂NR(COR), NR(COR), CONR₂, NO₂, SO₃ M, SO₃ NR₄, and N═NR'; or A is alinear, branched or cyclic hydrocarbon radical, unsubstituted orsubstituted with one or more of said functional groups; R isindependently hydrogen, a C₁ -C₂₀ substituted or unsubstituted alkyl, aC₃ -C₂₀ substituted or unsubstituted alkenyl, (C₂ -C₄ alkyleneoxy)_(x)R" or a substituted or unsubstituted aryl; R' is hydrogen, a C₁ -C₂₀substituted or unsubstituted alkyl, or a substituted or unsubstitutedaryl; R" is hydrogen, a C₁ -C₂₀ substituted or unsubstituted alkyl, a C₃-C₂₀ substituted or unsubstituted alkenyl, a C₁ -C₂₀ substituted orunsubstituted alkanoyl or a substituted or unsubstituted aroyl; x isfrom 1-40; M is H, Li, Na, Cs, or K; and y is an integer from 1 to 5when Ar is phenyl, 1 to 7 when Ar is naphthyl, 1 to 9 when Ar isanthracenyl, phenanthrenyl, or biphenyl, or 1 to 4 when Ar is pyridinyl,or 1 to 2 when Ar is triazinyl.
 22. A method to improve waterfastness ofan image generated by an aqueous ink composition comprising the stepsof: incorporating into said composition a modified carbon product havingattached at least one organic group, the organic group comprising a) atleast one aromatic group or a C₁ -C₁₂ alkyl group, and b) at least oneionic group, at least one ionizable group, or a mixture of an ionicgroup and an ionizable group, wherein the at least one aromatic group orC₁ -C₁₂ alkyl group of the organic group is directly attached to thecarbon and the organic group is present at a level of from about 0.10 toabout 4.0 micromoles/m² of the carbon used based on nitrogen surfacearea of the carbon.
 23. The method of claim 22, wherein said inkcomposition is an ink jet ink composition.